1n4n

Petunia hybrida Flowers Produce Two Unique Plant Defensins
The flowers of petunia (Petunia hybrida) accumulate high levels of at least two defensins (PhD1 and PhD2) as part of their defense armoury against potential pathogen infection. In contrast to the well-described seed defensins (Class I), these petunia floral defensins are produced as precursors with anionic C-terminal propeptides (CTPP) in addition to a typical secretion signal peptide and central basic defensin domain (47 amino acids) (Class II). PhD1 and PhD2 isolated from petunia flowers lack the CTPP, suggesting that it is removed during or after transit through the secretory pathway. In addition to the eight canonical cysteine residues that define the plant defensin family, PhD1 and PhD2 is unique to this family in that it contains an extra pair of cysteines that form a fifth disulfide bond. Hence, Lay et al. (2003) have defined them as a new subclass of this family of proteins.

About this Structure
1N4N is a Single protein structure of sequence from Petunia x hybrida. Full experimental information is available from OCA.

Reference
Structure of Petunia hybrida defensin 1, a novel plant defensin with five disulfide bonds., Janssen BJ, Schirra HJ, Lay FT, Anderson MA, Craik DJ, Biochemistry. 2003 Jul 15;42(27):8214-22. PMID:12846570

Page seeded by OCA on Sun Jul 27 15:58:39 2008

Related References
Defensins - Components of the innate immune system in plants., Lay FT, Anderson MA, Curr Protein Pept Sci. 2005 Feb;6(1):85-101. PMID:15638771 - review pointing out the salient features of Class I and Class II plant defensins

Isolation and properties of floral defensins from ornamental tobacco and petunia. Lay FT, Brugliera F, Anderson MA. Plant Physiol. 2003 Mar;131(3):1283-93. PMID:12644678 - original paper detailing the purification, expression and activity of PhD1 and PhD2

--Fung Lay 04:27, 1 August 2008 (IDT)